Hi,
I experienced seg faults due to stack corruption when calling statfs() with an automatic struct statfs variable.
It seems there is a mismatch between the struct statfs used by libc and that used by the arm64 kernel. The call to statfs() writes 120 bytes, but struct statfs is only 88 bytes. The attached test program shows this.
Building for arm64. libuClibc-1.0.30 kernel: Linux-4.17.3
Comparing these files:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tree... https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/libc/sysdeps/linux/co...
I see for the kernel all fields of struct statfs except f_fsid are the same length at 64 bits for arm64, and that gives 120 bytes. That differs from the libc version which has some 32 bit fields.
I filed this bug over at buildroot, but it was suggested to report it here:
https://bugs.busybox.net/show_bug.cgi?id=11121
The output of statfs-test program:
sizeof statfs: 88 sizeof packed: 138 1: 94 94 2: 19 19 3: 2 2 4: 1 1 5: 0 0 6: 0 0 7: 0 0 8: 0 0 9: 0 0 10: 10 10 11: 0 0 12: 0 0 13: 0 0 14: 0 0 15: 0 0 16: 0 0 17: 72 72 18: a5 a5 19: 7 7 20: 0 0 21: 0 0 22: 0 0 23: 0 0 24: 0 0 25: 83 83 26: 80 80 27: 7 7 28: 0 0 29: 0 0 30: 0 0 31: 0 0 32: 0 0 33: 83 83 34: 80 80 35: 7 7 36: 0 0 37: 0 0 38: 0 0 39: 0 0 40: 0 0 41: 72 72 42: a5 a5 43: 7 7 44: 0 0 45: 0 0 46: 0 0 47: 0 0 48: 0 0 49: d9 d9 50: a0 a0 51: 7 7 52: 0 0 53: 0 0 54: 0 0 55: 0 0 56: 0 0 57: 0 0 58: 0 0 59: 0 0 60: 0 0 61: 0 0 62: 0 0 63: 0 0 64: 0 0 65: ff ff 66: 0 0 67: 0 0 68: 0 0 69: 0 0 70: 0 0 71: 0 0 72: 0 0 73: 0 0 74: 10 10 75: 0 0 76: 0 0 77: 0 0 78: 0 0 79: 0 0 80: 0 0 81: 20 20 82: 0 0 83: 0 0 84: 0 0 85: 0 0 86: 0 0 87: 0 0 88: 0 0 89: 0 0 90: 0 0 91: 0 0 92: 0 0 93: 0 0 94: 0 0 95: 0 0 96: 0 0 97: 0 0 98: 0 0 99: 0 0 100: 0 0 101: 0 0 102: 0 0 103: 0 0 104: 0 0 105: 0 0 106: 0 0 107: 0 0 108: 0 0 109: 0 0 110: 0 0 111: 0 0 112: 0 0 113: 0 0 114: 0 0 115: 0 0 116: 0 0 117: 0 0 118: 0 0 119: 0 0 120: 0 0 121: ff cc 122: ff cc 123: ff cc 124: ff cc 125: ff cc 126: ff cc 127: ff cc 128: ff cc 129: ff cc 130: ff cc 131: ff cc 132: ff cc 133: ff cc 134: ff cc 135: ff cc 136: ff cc 137: ff cc 138: ff cc
-Geoff